I put a thermometer probe in a bowl with a lid and small hole for probe and filled bowl approx 2/3 with water. Water is holding at 99.6 degrees but temp readings in bator are 101.5 at shut off and 94 ish when lights switch on. Homemade wiggler has been in the bator for 2 days and has held constant.

I've never heard of anyone using a jar of water for a wiggler. So I can't tell you how it would compare to the consistancy of an egg. I can tell you how to make one out of baggies that works real well that I found on this site.

Actually it takes 3 sandwich size zip lock baggies. Fill the 1st one 1/4 to 1/3 full of water, push all the air out of it, seal it. Put in in another baggie,push all air out of it, seal it. flatten these out. Put these to inside another baggie, flatten out, push all air out,seal it Roll baggies up to to form like a tube type thing. Take your probe ,put in the middle of it ,Use rubber bands or duct tape to go around the ends of it to hold it all together. Got it?

No mistake I should have clarified. Thank you!
I am just very new to the homemade things as I have been using my LG's which have worked great for me, but I can't put in the larger eggs, so I built one.

I will try the baggie idea and see if stays as steady as the bowl.

But back to my original question: if it is holding the temp in there is there a chance that it could work?